Altered EEG Microstate Associated With Anxiety and Somatization Symptoms in Major Depressive Disorder

qinfan Shan¹Guisen Wu¹Yuxuan Xiong¹Qian Guo¹Hao Hu¹Fuxu Zhang¹Zhenying Qian²Tianhong Zhang^1,2*Xiaohua Liu^1,2*

• ¹Department of Psychiatry, Shanghai Mental Health Center,Shanghai Jiao Tong University School of Medicine, Shanghai, China
• ²Shanghai Key Laboratory of Psychotic Disorders, Shanghai Mental Health Center,Shanghai Jiao Tong University School of Medicine, Shanghai, China

Objective: To examine abnormalities in EEG microstate dynamics in patients with major depressive disorder (MDD) and to explore their associations with anxiety and somatization symptoms. Methods: We enrolled 30 patients with MDD and 40 healthy controls. Resting-state EEG was recorded and analyzed using microstate segmentation (classes A–D). Temporal parameters (mean duration, occurrence, time coverage, and transition probabilities) were compared between groups, and correlations with clinical symptoms (HAMD, HAMA, MADRS) were examined. Results: Compared with controls, patients with MDD exhibited a significantly longer duration, higher occurrence, and greater time coverage of microstate C, while microstate B showed reduced occurrence and coverage. Transition probability analyses revealed fewer transitions from A to B, A to D, B to A, B to D, and D to A, and more transitions between C and D. Symptom correlations indicated that microstate B occurrence was positively associated with HAMD anxiety/somatization scores, while transitions from C to D and from D to C were negatively correlated with anxiety/somatization scores. Conclusions: MDD is characterized by alterations in microstate B and C dynamics and disrupted transitions between C and D, some of which relate to symptom dimensions, suggesting that EEG microstate features may serve as potential neurophysiological markers in major depressive disorder.